Elastic fluid power plant



ELASTIC FLUID POWER PLANT Filed May 29, 1939 Inventor: Albert Stubbs by jpb7g H is Attorney.

Patented Mar. 5, 1940 UNITED STATES ELASTIC FLUID POWER PLANT Albert Stubbs, Knutsford, England, assignor to General Electric Company, a. corporation of New York Application May 29, 1939, Serial No. 276,469 In Great Britain June 3, 1938 2 Claims.

The present invention relates to elastic fluid power plants, more particularly to arrangements for operating auxiliaries, such as pumps and fans or blowers, required in connection with is forced circulation type boilers, although it is not necessarily limited thereto. In most cases the load on a boiler varies appreciably, requiring frequent adjustment by the operator of the speeds of the auxiliaries and in particular the circulating pump in the case of forced circulation type boilers.

The object of my invention is to provide an improved arrangement of power plant auxiliaries to minimize such manual adjustment and to cause the speeds of the auxiliaries to vary automatically in accordance with the load.

This is accomplished in accordance with my invention by the provision of an arrangement in which at least some of the auxiliaries are operated by motor generators controlled in response to load changes on the boiler. In a preferred embodiment the auxiliaries are motordriven with the motors supplied from an auxiliary turbo-generator having a turbine supplied with elastic fluid from an intermediate stage of a main turbine or turbine arrangement. In many cases the auxiliary turbine may be insufficient to operate all of the auxiliaries. In such cases one group of auxiliaries may be operated in accordance with my invention by an independently driven generator which is controlled in response to load changes of the boiler and which also may serve for starting the plant.

For a better understanding of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

The single figure of the drawing illustrates diagrammatically a power plant in, accordance with my invention.

The arrangement as shown in the drawing comprises a boiler I of the forced circulation type having a preheating element ll located in the convection space and a main heating element 12 located in the combustion space and connected in series with the preheating element H. Operating fluid such as water is forced through the heating elements and evaporated in the main element by means including a circulating pump [3 discharging into the inlet of the element ll. During operation vapor is discharged from the element l2 into a consumer, in the present instance a high pressure main turbine l4 having an inlet valve l5 and arranged to drive a generator IS. The main turbine M is connected through a reheater I! located in the convection space of the boiler in series with other consumers, such as an intermediate pressure turbine l8 and a double flow low pressure 5 turbine l9 driving a generator 20.

The auxiliaries for operating the boiler include the aforementioned circulating pump [3, a forced draft fan 2| for forcing air into the combustion space of the boiler, a mechanical stoker 10 22 near the bottom of the combustion space for moving combustible materials and an induced draft fan 23 located in the upper portion of the convection space to induce a draft from said space into a stack 24. The aforementioned aux- 5 iliaries and others such as condenser pumps, not shown, are operated by electric motors 25, 26, 21 and 28 respectively. These motors are divided into two groups. In the present instance the motors 26 and 21 form one group supplied 20 from a turbo-generator including a generator 29 driven by an auxiliary turbine 30 having an inlet conduit 3| connected to an intermediate stage of the main turbine arrangement, that is, to a point at which the pressure or like fluid com 25 dition varies in proportion to load changes of the boiler. In the present example the inlet conduit 3| is connected to an intermediate point of the reheater ll. The second group of motors is formed by the motors 25 and 28 and these motors are supplied with electric energy from a separate generator 32 which is driven by an independent engine, in the present example a combustion engine 33. The generator 32 has a field 34 excited in response to load changes of the boiler, such as by the provision of an exciter 35 driven from the auxiliary turbine 30 and connected to the field 34.

Having described the method of operation of my invention, together with the apparatus which 40 I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by 45 Letters Patent of the United States, is l l. A power plant including the combination of a boiler, consumers connected to the boiler, pumps and fans for operating the boiler, said pumps and fans forming two groups, means for 50 driving one group including an auxiliary turbine connected to a point of the consumers at which the fluid condition varies in proportion to load changes of the boiler, means for driving the other group including an independently driven 5' auxiliary generator having a field, and means exciting the field in response to load changes of the boiler.

2. A power plant including the combination of a boiler, a turbine arrangement connected to the boiler, motor-driven pumps and fans for operating the boiler, and means for supplying electric energy to the motors comprising an auxiliary turbo-generator having a turbine connected to an intermediate point of the turbine arrangement and a generator connected to some of the motors, and an independently driven auxiliary generator connected to other motors, and means for exciting the independently driven generator comprising an exciter driven from the auxiliary turbine.

ALBERT STUBBS. 

